An air filter in an MX5 NB (1998–2000) serves as the first line of defense between outside air and the engine compartment. The filter traps dirt particles while allowing air to flow as freely as possible toward the intake and combustion chamber. As a filter becomes clogged, resistance builds up in the airflow, and you’ll often notice that the engine’s response and breathing feel slightly less free. When the intake side of the intake manifold and sensors also remain clean and in good working order, the engine benefits directly.
